Master clock



T. s. CASNER MASTER CLOCK April 29, 1924 Original Filed Oct. 22. 1920 -2 Sheets-She et Inrea/dr April 29 1924. I 1,492,318

T. S. CASNER MASTER CLOCK- Original Filed Odt. 22', 1926 v 2 Sheets-Sheet. 2

v I a a I v I Patented Apr. 29, 1924 UNITED STATES 7 1,492,318 PATENT OFFICE.

THADDEUS STEPHENS CASNER, OF PLAINFIELD, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO GEORGE RAWAIL'OI NEW YORK, N. Y.

MASTER CLOCK.

Application filed October 22, 1920, Serial No. 418,697. Renewed Mar-ch24, 1924.

To all whom it may concern:

Be it known that I, THADDEUS STEPHENS 'Casxnn, a citizen of the United States, and residing at Plainfield, Union County, State of New Jersey, have invented certain new and useful Improvements in Master Clocks, of which the following is a specification.

The piesent invention relates to clocks, and particularly to master clocks which are adapted to be installed with a system of secondary electric clocks to accurately measure time intervals and periodically close a circuit through the several secondary clocks, causing them to advance their hands or other time indicating elements to indicate the passage of time. In the design of master clocks it is desired to obtain extreme accuracy as well as simplicity and compactness.' It is also desired to devise such a clock which will operate for long periods of time without attention, such as rewinding, and it is also important, where such a clock is electrically driven, to use the smallest amount of current ossible, to not only cut down the expense 0 running it, but also to prolong the life of the dry or other cells commonly used for this purpose, so that they need to be replaced only at long intervals of time.

Briefly stated, therefore, the objects of the present invention are, to rovide a master clock which is electrically riven and which uses the least possible amount of power; which requires the minimum care and attention; which measures time accurately; which is compact and may be made of small size; and the component parts of which are of standard design and easy to assemble together. The clock is therefore desi ed to use battery power which is applieg at frequent intervals and only for short periods of time and the arrangement of gearing is such that the power is applied near the escapement shaft, thereby cutting down to a minimum the frictional loss through the gearing to the hands and to the escapement. The power required to drive the clock is thereb reduced to a minimum. A novel means or quickly making and breaking a circuit connected to the cells furnishing the power is also provided to avoid arcing and consequent loss of power. Another feature of the clock lies in the particular novel means for making and breaking a circuit through the several secondary ;Figure 2;

clocks, this circuit breaking mechanism bemg of the utmost simplicity and reliability. Other features of the invention will be apparent from its disclosure in the following description and in the accompanying draw- 111? in which:

igure 1 is a section on the line '11 of Fi ure 2;

igure 2 is a side elevation of the clock mechanism, the casing and dial not being shown;

v Figure 3 is a section on the line 3-3 of Figure 2, certain of the movableparts being shown in a different position igure 4 is a section on the line 4-4 of Figure 2;

Figure 5 is a section on the line 5-5 of Figure 4;

Figure 6 is a section on the line 66 of Figure 5;

Figure 7 is a similar section but showing the parts in different position;

Figure 8 is a section on the line 88 of Figure 9 is an elevation of a modified form of escapement.

The clock frame is of usual construction having front and back plates 10 and 11 respectively and suitable members for holding these plates in spaced relation, and rotatably mounted in the.frame are five parallel shafts, the minute shaft 12, intermediate shaft 13, second shaft 14, intermediate shaft 15 and escapement shaft 16. The hour sleeve is indicated at 17 and is operatively connected to the minute shaft by the usual reducing gearing. Pinion 21 of the reducing train is fixed on the shaft 12, and the shaft is driven by the large gear 20 which is frictionally connected thereto through the spring 18 confined between this gear and the pin 19 passing through the shaft. On the intermediate shaft 13 are mounted a gear Wheel 22 and a pinion 23 which is integral with the gear wheel and which meshes with the large gear 20.

Fast on the shaft 14 is a. gear wheel 2 which is integral with the pinion 25 meshing with the gear 22 and the gear wheel .24 in turn meshes with a pinion 26 on the shaft 15 which pinion is rigidly connected to or integral with a gear 27 which in turn meshes with a pinion 28.secured on the escapement shaft 16 for rotation therewith.' It will be seen therefore that the five ro-' tatable shafts are all geared together so that if one rotates all must rotate. Driving power is applied to the middle shaft 14 and communicated in each direction through the intermediate shafts 13 and 15 t0 the minute shaft 12 and to the escapement shaft 16. It will be seen that this arrangement of shafts and gearing is such that the minimum amount of power may be used to move the hands and to drive the escapement, the power being centrally located and operatively connected with the minute shaft and escapement shaft through the minimum number of means permissible.

The electro-magnetic means for driving the second-shaft 14 comprises an electro-' magnet M secured to the frame and having pole pieces P, P extending laterally therefrom and terminating at points directly above and below and equidistant from the shaft 14. Rotatably mounted on this shaft and lying between the ends-of the pole pieces is a Z-shapcd armature A. Extending forwardly from this armature IS a pin 29 having a pawl 30 mounted on its end which pawl is normally pressed by a small spring 31 against the teeth of a pinion 32 fast on the shaft 14. It will be seen therefore that a clockwise movement of the armature (Figures 1 and will produce a rotation of shaft 14 and hence of the minute shaft and hour sleeve, and also of the escapement shaft. but that in moving in a reverse direction the pawl 30 will merely ride over the teeth of the small ratchet wheel 32.

Assuming the armature to be in the position illustrated in dotted lines in Figure 1, it will be apparent that an energization of the electromagnet M will result in a movement of the armature intoits full line position, as shown in Figure 3, and this move-- ment which occurs periodically is known as the rewinding movement. This rewinding movement is for the purpose of rewinding or tensioning a coiled driving spring 33. one end of which is secured to the armature and the other end of which is secured to a toothed wheel 33 (Figure 8) which lies within an annular supporting member 34 riveted to the frame and one end 34' of which constitutes a spring pawl which engages the toothed wheel 33 to prevent its rotation when the spring is wound. By means ofthe wheel 33, which may be rotated by inserting an instrument in one of the openings 33 the tension of the spring may be adjusted as desired.

The armature A also supports a forwardly extending pin or stud 35 provided for the purpose of rocking the lever 36 pivoted to the frame, the pin 35 engaging the lower arm 36' of this lever as the armature approaches a vertical position and the upper arm 86" of this lever as the armature approaches a horizontal position, a spring 37 being provided to complete the rocking movement of'the lever in either direction by a snap action after the initial movement has been imparted thereto by the in 35. This spring 37 has one end fastene to the frame at 38 and its other end to the lever 36 and normally exerts a pressure against the lever. It will be obvious that if the spring exerts a pressure on the end of the lever 36 at a point above the line connecting the pivotal point of the lever and point 38 that the lever will tend to tip downward about its pivotal point (Figure 3) but that if the spring exerts a pressure on the lever at a point lying below a line connecting'the point 38 with the pivot of the lever that the latter will be spring pressed upwardly (Figure 1). The function of the pin 35 is therefore to impart only initial movement to the lever 36 and the function of the spring 37 is to complete the movement of the lever with a snap action.

The rocking movement of the lever 36 is limited in each direction by the contact of the lower and upper arms 36 and 36 with the hub 39 on the shaft 14. The lever 36 has an upwardly extending arm 40 which is adapted to strike, when the lever snaps upwardly, an insulating plate 41 secured to a spring 42 and to drive the spring 42 against a similar spring 43 lying parallel thereto, these springs comprising the contacts of an electrical switch controllin the circuit through the electro-magnet h Assuming the coiled spring 33 to be wound up and the armature in the position illustrated in Figure 3, it will be seen that as the spring unwinds gradually the armature will be moved to the position illustrated in Figure 1, it having caused the lever 36 to snap upwardly as it approaches this position to thereby close the circuit through the electro-magnet. Immediately upon the closing of this circuit the armature is moved to the position illustrated in Figure 3 the pin 35 rocking the lever 36 in the reverse direction, whereupon the springs 42 and 43 separate and the circuit through the electro-magnet is broken.

The unwinding of the spring is controlled by the escapement illustrated in Figures 1 and 2. On the rear end of the escapement shaft 16 is secured the arm or (POSS piece 44 having a rearwardlv ext nding eccentric pin or crank 45 which passes through the slot 46 in the top plate 47 of the pendulum. this top plate being hung by a leaf spring 48 to the frame of the clock and being provided at its lower end with apertures 49 into which suitable hooks on the upper end of a pendulum of any desired type may be placed. The spring tends to impart a continuous rotation to the escapement shaft 16 and pin 45, except when the rewinding is being accom lished, and the pin makes a. half revo ution about the axis of shaft 16 at each stroke of the pendulum, the impulse being iven to the pendulum on vertical faces 0% the slot 46 and the horizontal portions ofthe slot allowin the pendulum to swing laterally througfi its lateral amplitude ofvibration, the pin riding in the horizontal portion of the slot during this time and again exerting an impulse on the pendulum when it re-enters the vertical slot.

In the construction just described the spring 33 is adapted to be rewound four times each minute but the inertia of the pendulum is sufiicient to continue its swing during the very short interval of time when the magnet is energized and the spring is being rewound, during which time it of course exerts no pressure tending to drive the pendulum;

shaped insulating block 52 and on this block rests the ends of spring contact fingers 50 and 51 which are connected by suitable wires in the secondary clock circuit. The spring contact 50 is somewhat shorter than the spring contact 51 and also has a flange 51 which extends upwardly and laterally over the spring contact 51. The shaft 14 and hence the block 52 rotates once each minute in a clockwise direction (Figure 4) and it will be seen that the shorter spring finger 50 will fall down the radial face of the cam a short time before the spring finger 51 falls. When this takes place the flange 51' of the spring finger 50 will make contact with the spring finger 51 and complete the circuit through the secondary clock system. Very soon after the circuit is completed however it is again broken. that is, when the spring finger 51 also falls. The time of contact is of course dependent upon the difference in length between the spring fingers and this,is usually regulated so that the contact has a duration of approximately two seconds. giving the mechanisms of the secondary clocks ample Itime i to complete their functions.

In Figure 9 I disclose a modified form of the escapement. the crank pin 4-5 being adapted to exert its driving impulses on the vertical faces of the blocks 60, which may be of hardened steel. bronze, or may heijewels, and are secured to the pendulum .platc livscrews so that they may b'e adinsted. This; escan'ement however operates in exactly 'the same manner as the escapei nent illustrated in Figureshiland 2, the crank 45 giving an impulse to the pendulum at each stroke thereof, the pin making a half revolution about the escapement shaft at each beat. Various other modifications may be employed and it is obvious that if desired a different form of escapement may be utilized'instead of a pendulum, although this is a master clocks. T 1e design and arrangement of the various elements of the 1nvention may be changed and it willbe understood that the invention is not limited in its scope to the exact embodiment abovedescribed and illustrated in the drawing.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. In an electric clock, in combination, a frame, a shaft rotatably supported in the frame, and means for rotating the shaft at uniform speed comprising an armature loosely mounted on the shaft, a clutch device operatively connecting said armature and shaft, a coiled spring concentric with the shaft and having one end secured to the frame and the other connected to the armature, an electro-magnet for intermittently actuating the armature to wind the spring, means for automatically energizing the electro-magnet when the spring becomes unwound, and means for adjusting the tension of the spring.

2. In an electric clock, in combination, a frame, a shaft rotatably supported in the frame and means for rotating the shaft at uniform speed comprising an armature loosely mounted on the shaft and operatively connected thereto, a rotatable member arranged concentrically of said shaft, means secured to the frame for locking said member against rotation, a coiled spring con referred escapement for centric with the shaft and having one end fixed to the frame and the other connected to the armature, an electro-magnet for intermittently actuating the arn'iaturc to wind the spring, and means for automatically energizing 3. In an electric clock, in combination, a frame, a shaft rotatably supported in the frame and means for rotating the shaft at uniform speed comprising an armature (loosely inounted on the shaft and operatively connected thereto, a rotatable member arranged concentrically with said shaft and having a to thed periphery a dog supported on said fr, me andnormally engaging a tooth "of said member to prevent rotation thereof but being adapted to be disengaged from aid tooth to permit rotation of said meifi shaft and having one end fixed tothe frame a d the other connected to the armature, an e ectro-magnet for intermittently actuating the armature to wind the spring, and means for automatically energizing the electromagnet when the spring becomes unwound.

4. In an electric clock, in combination, a frame, a shaft rotatably supported in the frame, and means for rotating thev shaft at the electro-magnet when the spring, becomes unwound. i

, a coiled spring concentric ,ivith the uniform speed comprising an armature loosely mounted on the shaft, a clutch device operatively connecting said armature shaft, a coiled spring concentric with the shaft and having one end secured to the frame and the other connected to the armature, an electromagnet for intermittently actuating the armature to windthe spring, a switch controlling the energization of said electromagnet, a lever controlling said switch, said lever having spaced arms and said armature having a projection to contact with said arms whereby the switch is controlled in accordance with the position of the armature.

5. In an electric clock, in combination, a frame, a shaft rotatably supported in the frame, and means for rotating the shaft at uniform speed. comprising an armature loosely mounted on the shaft, a clutch device operatively connecting said armature shaft, a coiled spring concentric with the shaft and having one end secured to the frame and the other connected to the armature, an electro-magnet for intermittently actuating the armature to wind the spring. a switch controlling the energization of said electromagnet, a lever for opening and closing said switch, said lever being disposed parallel with the armature and having spaced arms. a pin projecting from the armature and adapted to contact with either of said arms to move the lever, and a spring for completing the swinging motion of the lever after initial motion has been imparted thereto.

6. In an electric clock, in combination, a rotatable shaft, mechanism for driving said shaft at uniform speed in one direction, and a switch adapted to be closed and o ened at each revolution of the shaft, sai switch comprising two relatively movable conducting members substantially parallel to each other and having free ends adjacent said shaft and terminating indifferent vertical planes parallel to said shaft, one of said members having a portion projecting laterally toward the other but normally out of contact therewith, and a cam member of insulating material fixed on said shaft and supporting the ends of said members, said cam having a peak terminating at a radial face, rotation of said cam causing the ends of said members to fall from said peak down said radial face, one of said members falling before the other and contact being established between said members throu h said projecting portion after one of sai members has fallen over said peak but before the other has fallen. 4

In testimony whereof I afiix my signature.

THADDEUS STEPHENS CASNE-R. 

